1 X.. Wang, N.. Saleh, M.. Krishnan, H.. Wang, S.. Backus, M.. Murnane, H.. Kapteyn, D.. Umstadter, Q.. Wang, and B.. Shen, Journal of the Optical Society of America B 20, (2003).
1 X.. Wang, W.. Yu, S.. Backus, M.. Murnane, H.. Kapteyn, and D.. Umstadter, in Unknown (IEEE, Chiba, Japan, 2001).